Grain refinement of intermetallic compounds in the Cu–Sn system under high pressure torsion

• Published in: Materials letters 2016-09, Vol.179, p.12-15
• Main Authors: Korneva, A., Straumal, B., Chulist, R., Kilmametov, A., Bała, P., Cios, G., Schell, N., Zięba, P.
• Format: Article
• Language: English
• Subjects: Copper base alloys; Cu–Sn alloy; Dislocation density; Grain boundaries; High-pressure torsion; Intermetallic compounds; Intermetallics; Microstructure; Nano-crystalline metals; Phases; Plates; Thermodynamics and kinetics; Torsion
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2016.05.059

The Cu–36wt% Sn alloy was subjected to the high pressure torsion (HPT) at room temperature. Before deformation the microstructure was composed of alternating coarse-grained plates of the ζ and ε compounds (Hume-Rothery electronic phases). HPT led, as usual, to the strong grain refinement and increase of dislocation density. However, the macroscopic shape of ζ and ε plates remained unchanged. It means that the refinement took place in each phase individually, i.e. inside the respective ζ and ε plates. High angle grain boundaries are more pronounced in ε phase. This unusual behavior of the alloy is connected with a high hardness of the ζ and ε intermetallic compounds. [Display omitted] •As cast Cu–36wt% Sn contains the alternating ε and ζ coarse-grained plates.•After high pressure torsion the ε and ζ phases become ultrafine-grained.•However, the shape of ε and ζ plates remains unchanged.•This unusual behavior is due to the high hardness of ε and ζ phases.